How to block that sun

The link between sun exposure and skin cancer has been well documented in recent years, and most people understand that what looks like a healthy glow often is the opposite. It can take as long as 20 years for skin cancer to surface — meaning those carefree days spent cavorting on the beach in your youth can come back to bite you decades later. But don’t feel that the damage has been done and it isn’t worth taking steps now to protect your skin. Some preventive steps are easy: stay in the shade, avoid tanning beds, wear a hat. But when it comes to sunblock, the many products available, the long list of chemical names in the ingredient list and the many urban myths about what to use when and how can leave some people feeling like it’s easier just to say no to sunblock.Here are some tips to help make it all less confusing.First, there is a difference between sunscreen and sunblock, though the words are often used interchangeably. Sunscreen absorbs ultraviolet light, allowing some light through to the skin. Sunblock physically blocks UV rays. Most cosmetics with sun protection contain sunscreens, which are generally lighter and less greasy.Look for a product that will combat both UVA and UVB rays. The best choices will have both a sunscreen and a sunblock. Ingredients to look for in a sunblock are titanium dioxide, iron oxide or zinc oxide. For a sunscreen, check the ingredient list for octinoxate, octisalate, oxybenzone, benzophenone or menthol anthranitate.As for which SPF to choose: the higher the better. Most dermatologists recommend an SPF of at least 15 for daily use. But for a summer vacation at the beach, go higher. Manufacturers claim that blocks with high SPFs need fewer applications, but experts aren’t in complete agreement. While it seems that SPF 100 will give you more protection than SPF 50, the percentage increase is very small. Diligent reapplication is the best defense.Sunblocks expire. Check for an expiration date and throw out any open bottles at the end of the summer — they will not offer protection the following year.Apply sunblock 15 to 30 minutes before going outside and reapply every two hours. And don’t forget to reapply after every swim.It should take about two shot glasses full of sunblock to cover an adult, so don’t skimp. When in doubt, use more. Also, be aware that the sun can burn through the clouds on overcast days and that the peak burning time is between 10 a.m. and 4 p.m.